12
12-31
Ver.0.10
SERIAL I/O
12.3 Transmit Operation in CSIO Mode
12.3.3 Starting CSIO Transmission
When all of the following transmit conditions are met after you finished initialization, the serial I/O
starts transmit operation.
(1) Transmit conditions when CSIO mode internal clock is selected
• The SIO Control Register's transmit enable bit is set to 1.
• Transmit data (8 bits) is written to the lower byte of the SIO Transmit Buffer Register (transmit
buffer empty bit = 0).
(2) Transmit conditions when CSIO mode external clock is selected
• The SIO Control Register 0's transmit enable bit is set to 1.
• Transmit data is written to the lower byte of the SIO Transmit Buffer Register (transmit buffer
empty bit = 0).
• A falling edge of transmit clock on the SCLKI pin is detected.
Note 1 : While the transmit enable bit is cleared to 0, writes to the transmit buffer register are
ignored. Always be sure to set the transmit enable bit to 1 before you write to the
transmit buffer register.
Note 2 : When the internal clock is selected, a write to the lower byte of the transmit buffer
register in Note 1 above triggers a start of transmission.
Note 3 : The transmit status bit is set to 1 at the time data is set in the lower byte of the SIO
Transmit Buffer Register.
When transmission starts, the serial I/O transmits data following the procedure below.
• Transfer the content of the SIO Transmit Buffer Register to the SIO Transmit Shift Register.
• Set the transmit buffer empty bit to 1. (Note)
• Start sending data synchronously with the shift clock beginning with the LSB.
Note : A transmit buffer empty interrupt request and/or a DMA transfer request can be generated
when the transmit buffer is emptied.
12.3.4 Successive CSIO Transmission
Once data is transferred from the transmit buffer register to the transmit shift register, the next data
can be written to the transmit buffer register even when transmission of the preceding data is not
completed. When the next data is written to the transmit buffer before completion of the preceding
data transmission, the preceding and the next data are successively transmitted.
To see if data has been transferred from the transmit buffer register to the transmit shift register,
check the SIO Status Register's transmit buffer empty flag.
Summary of Contents for M32170F3VFP
Page 42: ...1 1 24 Ver 0 10 OVERVIEW 1 4 Pin Layout This is a blank page ...
Page 56: ...2 2 14 Ver 0 10 This is a blank page ...
Page 88: ...3 3 32 Ver 0 10 ADDRESS SPACE 3 7 Notes on Address Space This is a blank page ...
Page 270: ...9 9 40 Ver 0 10 DMAC 9 4 Precautions about the DMAC This is a blank page ...
Page 614: ...12 12 64 Ver 0 10 This is a blank page SERIAL I O 12 9 Precautions on Using UART Mode ...
Page 756: ...17 17 10 Ver 0 10 RAM BACKUP MODE 17 4 Exiting RAM Backup Mode Wakeup This is a blank page ...
Page 762: ...18 18 6 Ver 0 10 OSCILLATION CIRCUIT 18 2 Clock Generator Circuit This is a blank page ...
Page 831: ...CHAPTER 22 CHAPTER 22 TYPICAL CHARACTERISTICS 22 1 A D Conversion Characteristics ...
Page 833: ...Appendix 1 1 Dimensional Outline Drawing APPENDIX 1 APPENDIX 1 MECHANICAL SPECIFICATIONS ...
Page 841: ...Appendix 3 1 Precautions about Noise APPENDIX 3 APPENDIX 3 PRECAUTIONS ABOUT NOISE ...